This idea is shamelessly derivatized from the linked idea.
As [Skewed] pointed out in an underpunctuated but
otherwise promising post, human foetuses or neonates
injected with pig stem cells would grow up to be
immune-
tolerant towards donor organs from clones of the original
pig.

This
is OK, but it runs the risk that, every time you
sunbathe, people are going to sniff and ask "can anyone
else smell bacon"?

So.

Instead of using pig stem cells, just inject every newborn
with a cocktail of stem cells from as many humans as
possible. With a bit of luck, such children will grow up
being immune-tolerant to the entire human population.

As a result, they will be able to accept donated organs
from anyone, rather than hoping that the next wet-
weather motorcyclist is a match.